A Randomized, Multicenter, Open-Label, Two-Arm, Phase III Neoadjuvant Study Evaluating Trastuzumab Emtansine Plus Pertuzumab Compared With Chemotherapy Plus Trastuzumab and Pertuzumab for Patients With HER2-Positive Breast Cancer

This is a randomized, multicenter, open-label, two-arm study in treatment-naive participants
with operable, locally advanced, or inflammatory, centrally-assessed HER2-positive early
breast cancer (EBC) whose primary tumors were greater than or equal to (>/=) 2 centimeters
(cm). The study was designed to evaluate the efficacy and safety of trastuzumab emtansine +
pertuzumab (experimental arm; T-DM1 + P) versus chemotherapy, trastuzumab + pertuzumab
(control arm; TCH + P). The study comprised a neoadjuvant treatment period, followed by
surgery, and an adjuvant treatment period.

Treatment can be stopped due to disease recurrence, unacceptable toxicity, withdrawal of
consent, or study termination.